1. Field of the Invention
The present invention relates to the field of connection technology, and relates in particular to a connecting box for connection of wiring to an appliance, in particular for connection of wiring to a photovoltaic module (photovoltaic collector, solar panel, solar cell).
2. Description of Related Art
Photovoltaic solar installations are generally of modular design and comprise a multiplicity of solar cells which are connected via external wiring. In order to achieve a higher voltage, the individual solar cells are connected at least in groups in series, by the positive pole of a first solar cell being connected to the negative pole of a further solar cell. One problem that arises in this case is that, when a solar cell is partially covered, for example, as a result of a shadow thrown by surrounding objects or by clouds, this solar cell becomes passive and contributes only slightly, if at all, to the electricity production. In consequence, when connected in series, the current from the adjacent solar cell flows through the covered solar cell, which can thus be damaged or, at least, its life may be reduced. For this reason, it is known for solar cells to be temporarily bridged by means of an electronic circuit, which generally has diodes as protective elements, and thus to be decoupled from the electricity production during the disturbance. These electronic circuits are frequently accommodated in connecting boxes which are at the same time used for connection of the wiring.
EP999601 from Sumitomo Wiring Systems Ltd. discloses a connecting box for solar cells having a housing with a lower and an upper cover, which can be connected to one another via plug connections. The upper cover has connections for external electrical wiring, as well as electrical plug contacts which are arranged such that, when the housing is in the closed position, they result in an electrical connection to corresponding electrical contacts on the lower cover. Diodes are arranged in the upper cover, and are used for protection of the solar cell. In order to make the arrangement weather-resistant, the diodes are encapsulated in a filler material, for example silicone. One particular disadvantage of these arrangements is that they are unsuitable for present-day high-power solar cells, since they have an inadequate cooling. A further disadvantage is that the proposed encapsulation in silicone unnecessarily increases the material consumption and the weight, and is time-consuming.
U.S. Pat. No. 6,582,249 from Tyco Electronics AMP GmbH discloses a connecting box for solar modules having a housing composed of plastic and having a cover which is connected to a hinge strip. The housing lower part has an opening for connections of a solar panel, and connections for external electrical wiring. Electrical components, for example diodes, are fitted between the connections in the housing lower part. The electrical components may be protected against direct contact by a protective cover which is fitted to the side inner wall of the housing such that it can pivot. The components are preferably encapsulated with a filler material through an opening in the protective cover, after the protective cover has been fixed in the correct position in the housing.
EP1605554 from Mantenimiento Instalaciones Malaga SL discloses a connecting box for solar cells having a housing lower part and a cover with a detachable plug connection. The housing has a first opening for connections of a solar cell, and a second opening for connections of external electrical wiring. A printed circuit board can be mounted in the housing by means of a screw.
German Utility Model DE202005018884U1, from Multi-Holding AG, discloses a connecting box for a solar panel. The connecting box has a housing lower part and a cover which is connected to the housing lower part such that it can pivot. The housing lower part has openings for connections of a solar panel, and has external electrical wiring. Contact elements for attachment of electrical components, in particular diodes, are provided in the interior of the housing. The contact elements are designed such that they are intended to absorb and dissipate the heat which is created by the diodes.
EP1501133 from Tyco Electronic AMP GmbH discloses a connecting box for a solar panel. The connecting box has a housing lower part and a cover which is connected to the housing lower part via a hinge such that it can pivot. In the area of the bottom, the housing lower part has an opening for connections of a solar panel and, in a side wall, it has openings for external electrical wiring. Busbars and contact elements are arranged in the interior of the housing. One embodiment has a printed circuit board with diodes, which are held firmly by holding elements of the housing.
JP20022359389 from Kitani Denki KK, discloses a connecting box for solar cells having a housing with a housing lower part and a removable cover. Openings in the area of the bottom of the housing lower part are used for connection to a solar panel. Openings in a side wall are used for connection of electrical wiring. Diodes which are arranged such that they can be replaced are used as protective elements.
DE102005044939 from Spelsberg Guenther GmbH Co KG discloses a connecting box for solar cells. The connecting box has a protective device, for example in the form of a bypass diode. The printed circuit board is connected to a cooling element, which is passed out of the housing and is connected to the frame of the solar panel, in order to dissipate heat.
One disadvantage of the connecting boxes which are known from the prior art is the inadequate cooling of the electronic components, and the thermal loading of the solar cells which this results in.
One object of the invention is therefore to disclose a connecting box which does not have the disadvantages to which the prior art is subject.
This object is achieved by the invention as defined in the patent claims.